Happily for Yoko Sakamoto, she didn't have to argue with her husband — also a Sakamoto — about whose last name they'd use when they married.

Not that the 47-year-old civil rights activist would have had much of an option: The law allows only one surname per family — customarily the man's.

"One's last name is a key part of one's self-identity," Sakamoto said. "It's wrong that any of us by law have to change surnames that we've used all our lives, and it is always the women who put up with the burden."